Interesting way of looking at it. Speaker purchases for me have always been big purchases, So I have probably owned only 5 pair in the last 50 years. Each represented a significant jump in cost and performance. Most were new, I guess when doing such an infrequent purchase I wanted the best performance available at the time.
I have noticed over this period was movement from big huge flabby inarticulate bass / drivers… to clear, clean, articulate bass (small long throw drivers) where individual bass lines became clearly defined. The treble has gone from primarily sizzling white distortion to (with good electronics) the highly detailed shimmering brass of real instruments.
So the difference has been huge… but gradual so it doesn’t seem any few years made much of a difference.
I have noticed over this period was movement from big huge flabby inarticulate bass / drivers… to clear, clean, articulate bass (small long throw drivers) where individual bass lines became clearly defined. The treble has gone from primarily sizzling white distortion to (with good electronics) the highly detailed shimmering brass of real instruments.
So the difference has been huge… but gradual so it doesn’t seem any few years made much of a difference.